The present invention relates to a shop around refrigerated display case in which a consumer has access to products within the display case from a plurality of angular positions with respect to the display case.
The terms "refrigerated" and "refrigeration" as used throughout both the specification and claims of the present application are intended to refer to display cases maintained at temperatures both in excess of 32.degree. F., such as dairy food and fresh meat display cases, and below 32.degree. F., such as frozen food cases.
Most refrigerated display cases typically in use today are of a generally rectangular form having an access opening on only one side. A plurality of such cases are set up within a store extending along a plurality of rows. The condensers and compressors for such cases are generally mounted in a location separate from the cases with piping to the cases running under the floor of the store. While such display cases are fully acceptable for the majority of the displays within a store, particularly in the larger stores, such cases inherently lack a certain degree of versatility and flexibility. Since the piping for such display cases is prearranged under the floor of the store, there is no possibility for setting up spot displays within the store. In addition, such cases are set up in back-to-back arrangements with the access only being from one side. While it is often desirable to place additional refrigerated display units at the ends of such rows of cases, the only type of case typically available is another rectangular unit merely open from one side. Both the accessibility to the refrigerated products within the case and the maximum utility of space is significantly hampered by such an arrangement. In addition, such display cases only provide access to the consumer from one side of the case. In many situations, especially when there is limited space within the store, it is desirable if the consumer could have access to the products within the case from both sides of the case, or even more preferably, from all sides of the case.
In order to overcome some of the above-noted drawbacks of the typically utilized rectangular refrigerated display cases, various types of shop around refrigerated display cases have been developed. Exemplary of such cases are those illustrated in U.S. Pat. Nos. 2,929,227 to Rainwater; 3,009,333 to Rainwater; 3,115,019 to Rutishauser; 3,306,068 to Allgeyer et al.; 3,365,907 to Barroero; and 3,392,543 to Miller. Both of the patents to Rainwater illustrate open top refrigerated display cases having two compartments where air flows through a centrally located conduit that separates the two compartments. The patent to Miller illustrates two open-front display cases arranged in a back-to-back relationship with the cases sharing a common centrally located air conduit. The patents to Rutishauser, Barroero and Allgeyer et al illustrate self-contained refrigerated display cases presenting a 360.degree. opening for access into the case. The circular display cases illustrated in the patents to Rutishauser and Barroero contain complex air-flow paths in which the refrigerated air flows out of openings within each of the shelves spaced along the longitudinally extending conduit. The circular display case illustrated in the patent to Allgeyer et al. includes a single air conduit for providing a single refrigerated air curtain across the opening in the display case.
In summation, all of the above-noted patents either disclose refrigerated display cases in which full access to the products within the display case is not available to the consumer or in rendering a display case which provides for wider access, the display cases contain complex air flow arrangements rendering the systems significantly less efficient in properly maintaining refrigeration of the products within the display case. The difficulty of properly refrigerating the products is particularly significant due to the extensive open area with such circular display cases.
In the operation of all types of refrigerated display cases, it is desirable to include a system capable of automatically defrosting the display case. The defrost cycle can be actuated either at set periodic times or when the frost buildup within the system has reached a certain predetermined level. Such systems are typically thermostatically controlled so as to automatically switch between a refrigeration cycle and a defrost cycle of operation. In this manner of operation, it is possible to avoid any significant frost buildup within the display case.
Typically within the prior art, there have been three different approaches employed for defrosting refrigerated display cases. The three approaches include: utilizing electric resistance heaters; passing a compressed gaseous refrigerant through the refrigeration coils; and, circulating ambient air through the air conduit. Due to the increasing cost of energy in recent years, efforts have been made to place more emphasis on the utilization of ambient air defrost systems in place of the electrical resistence heaters or compressed gaseous refrigerant defrost systems.
One type of system that employs ambient air during the defrost cycle is exemplified by those embodiments illustrated in U.S. Pat. Nos. 3,403,525, 3,850,003 and 3,937,033, all to Beckwith, et al. These systems use fans separate and distinct from the main circulating fans. The additional fans are turned on only during the defrost cycle of operation for pulling ambient air from outside of the display case directly into the air conduits. A second type of system is illustrated in U.S. Pat. No. 3,082,612 to Beckwith, which system draws ambient air into the main circulation path through ports located in the lower front panel of the refrigerated display case. Such ports are normally closed during the refrigeration cycle and are opened during the defrosting cycle. The Beckwith, et al. U.S. Pat. No. 3,850,003 indicates that the concepts described in U.S. Pat. Nos. 3,082,612 and 3,403,525 did not prove to be practical and hence were not commercially feasible.
Another type of ambient air defrosting system is shown in U.S. Pat. No. 4,144,720 to Subera, et al., which is assigned to the same assignee as the present application. In the foregoing patent application, an open front refrigerated display case having primary and secondary air conduits is disclosed. In this system, the direction of air flow within one of the conduits is reversed, for example, by the use of reversible fans for ambient air defrost. U.S. Pat. No. 4,026,121 to Aokage et al., which illustrates an open front display case, and U.S. Pat. No. 4,120,174 to Johnston, which illustrates an open top display case, also disclose reverse ambient air flows for defrosting.